U.S. patent application number 11/951723 was filed with the patent office on 2008-04-03 for image processing apparatus.
Invention is credited to Motokazu Kashida, Kenji Kawai, Koji Takahashi.
Application Number | 20080079818 11/951723 |
Document ID | / |
Family ID | 27302644 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080079818 |
Kind Code |
A1 |
Takahashi; Koji ; et
al. |
April 3, 2008 |
IMAGE PROCESSING APPARATUS
Abstract
An image processing apparatus includes an image pickup circuit
having a plurality of photographic modes, such as television
standards, a compression processing circuit for performing
compression processing of an image pickup signal outputted from the
image pickup circuit, the compression circuit having a plurality of
compression modes, and a selecting circuit for selecting one of the
compression modes of the compression processing circuit in
accordance with a selected one of the photographic modes of the
image pickup circuit.
Inventors: |
Takahashi; Koji;
(Kanagawa-ken, JP) ; Kashida; Motokazu; (Tokyo,
JP) ; Kawai; Kenji; (Tokyo, JP) |
Correspondence
Address: |
COWAN LIEBOWITZ & LATMAN P.C.;JOHN J TORRENTE
1133 AVE OF THE AMERICAS
NEW YORK
NY
10036
US
|
Family ID: |
27302644 |
Appl. No.: |
11/951723 |
Filed: |
December 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11216806 |
Aug 31, 2005 |
7319812 |
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11951723 |
Dec 6, 2007 |
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10195266 |
Jul 15, 2002 |
7024101 |
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11216806 |
Aug 31, 2005 |
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08665766 |
Jun 19, 1996 |
6453120 |
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10195266 |
Jul 15, 2002 |
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08218574 |
Mar 28, 1994 |
5563661 |
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08665766 |
Jun 19, 1996 |
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Current U.S.
Class: |
348/222.1 ;
348/E5.031; 348/E9.01; 375/240.03; 375/E7.026; 375/E7.137;
375/E7.145; 375/E7.15; 375/E7.159; 375/E7.163; 375/E7.165;
375/E7.172; 375/E7.181; 375/E7.189; 375/E7.205; 375/E7.211;
375/E7.265; 375/E7.279; 386/E5.072 |
Current CPC
Class: |
H04N 5/772 20130101;
H04N 5/78266 20130101; H04N 9/7921 20130101; H04N 9/045 20130101;
H04N 9/7973 20130101; H04N 9/8047 20130101; H04N 5/9305 20130101;
H04N 19/142 20141101; H04N 19/162 20141101; H04N 19/593 20141101;
H04N 9/8205 20130101; Y10S 358/906 20130101; H04N 9/8042 20130101;
H04N 19/172 20141101; H04N 19/85 20141101; H04N 19/89 20141101;
H04N 19/98 20141101; H04N 5/23245 20130101; H04N 19/152 20141101;
H04N 7/0125 20130101; H04N 19/12 20141101; H04N 19/132 20141101;
H04N 19/137 20141101; H04N 19/61 20141101; H04N 9/04555 20180801;
H04N 9/04559 20180801; H04N 5/232939 20180801; H04N 5/775 20130101;
H04N 5/9261 20130101; H04N 9/797 20130101; H04N 5/78263 20130101;
H04N 9/7925 20130101; H04N 9/8063 20130101; H04N 19/112
20141101 |
Class at
Publication: |
348/222.1 ;
375/240.03; 348/E05.031; 375/E07.026 |
International
Class: |
H04N 11/02 20060101
H04N011/02; H04N 5/228 20060101 H04N005/228 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 1993 |
JP |
HEI 05-078225 |
May 21, 1993 |
JP |
HEI 05-142710 |
May 31, 1993 |
JP |
HEI 05-129373 |
Claims
1. A camera-integrated type digital image data recording apparatus
comprising: a) an image pickup unit, adapted to output digital
image data corresponding to a selected image size, wherein said
image pickup unit includes a sensor unit, an focus control unit, an
exposure control unit and a white balance control unit; b) a
selecting unit, adapted to select one of a plurality of image sizes
and one of a plurality of compression modes, wherein the selection
of an image size and the selection of a compression mode are
performed individually; c) an image size control unit, adapted to
set the image size selected by said selecting unit; d) a
compression mode control unit, adapted to set the compression mode
selected by said selecting unit; e) a quantization control unit,
adapted to determine a quantization parameter corresponding to the
compression mode set by said compression mode control unit; f) a
compression unit, adapted to compress the digital image data in
accordance with the compression mode set by said compression mode
control unit, wherein said compression unit includes a DCT unit, a
quantization unit and a coding unit; g) an adding unit, adapted to
add additional data corresponding to the image size and the
compression mode selected by said selecting unit to the digital
image data compressed by said compression unit; h) a recording
unit, adapted to record the compressed digital image data and the
additional data; i) a reproducing unit, adapted to reproduce the
recorded digital image data; and j) a display unit mounted on said
apparatus, adapted to display the digital image data output from
said image pickup unit or the digital image data reproduced by said
reproducing unit.
2. The apparatus according to claim 1, further comprising an
operation mode display unit, adapted to display mode information
corresponding to said selecting unit.
3. The apparatus according to claim 2, wherein the mode information
is an SD recording mode or an HD recording mode.
4. The apparatus according to claim 1, wherein said display unit
displays information indicative of time and date.
5. The apparatus according to claim 1, wherein said focus control
unit is controlled in accordance with the selection of the image
size.
6. The apparatus according to claim 1, wherein the compression mode
includes a plurality of compression ratios.
7. The apparatus according to claim 1, wherein the plurality of
image sizes include a plurality of image resolutions.
8. A camera-integrated type digital image data recording apparatus
comprising: a) an image pickup unit, adapted to output digital
image data corresponding to a selected image size, wherein said
image pickup unit includes a sensor unit, an focus control unit, an
exposure control unit and a white balance control unit; b) a
selecting unit, adapted to select one of a plurality of image sizes
and one of a plurality of compression modes, wherein the selection
of an image size and the selection of a compression mode are
performed individually; c) an image size control unit, adapted to
set the image size selected by said selecting unit; d) a
compression mode control unit, adapted to set the compression mode
selected by said selecting unit; e) a quantization control unit,
adapted to determine a quantization parameter corresponding to the
compression mode set by said compression mode control unit; f) a
compression unit, adapted to compress the digital image data in
accordance with the compression mode set by said compression mode
control unit, wherein said compression unit includes a DCT unit, a
quantization unit and a coding unit; g) an additional data
generating unit, adapted to generate additional data corresponding
to the image size and the compression mode selected by said
selecting unit; h) a recording unit, adapted to record the
compressed digital image data and the additional data; i) a
reproducing unit, adapted to reproduce the recorded digital image
data; and j) a display unit mounted on said apparatus, adapted to
display the digital image data output from said image pickup unit
or the digital image data reproduced by said reproducing unit.
9. The apparatus according to claim 8, further comprises an
operation mode display unit, adapted to display mode information
corresponding to said selecting unit.
10. The apparatus according to claim 9, wherein the mode
information is an SD mode or an HD mode.
11. The apparatus according to claim 8, wherein said display unit
displays information indicative of time and date.
12. The apparatus according to claim 8, wherein said focus control
unit is controlled in accordance with the image size set by said
image size control unit.
13. The apparatus according to claim 8, wherein the compression
mode includes a plurality of compression ratios.
14. The apparatus according to claim 8, wherein the plurality of
image sizes include a plurality of image resolutions.
15. A camera-integrated type digital image data recording apparatus
comprising: a) an image pickup unit, adapted to output digital
image data corresponding to a selected image size, wherein said
image pickup unit includes a sensor unit, an focus control unit, an
exposure control unit and a white balance control unit; b) a
selecting unit, adapted to select one of a plurality of image sizes
and one of a plurality of compression modes, wherein the selection
of an image size and the selection of a compression mode are
performed individually; c) an image size control unit, adapted to
set the image size selected by said selecting unit; d) a
compression mode control unit, adapted to set the compression mode
selected by said selecting unit; e) a quantization control unit,
adapted to determine a quantization parameter corresponding to the
compression mode set by said compression mode control unit; f) a
compression unit, adapted to compress the digital image data
corresponding to the image size set by said image size control
unit, in accordance with the compression mode set by said
compression mode control unit, wherein the compression unit
includes a DCT unit, a quantization unit and a coding unit; g) an
additional data generating unit, adapted to generate additional
data corresponding to the image size and the compression mode
selected by said selecting unit; h) a recording unit, adapted to
record the compressed digital image data and the additional data;
i) a reproducing unit, adapted to reproduce the recorded digital
image data; and j) a display unit mounted on said apparatus,
adapted to display the digital image data output from said image
pickup unit or the digital image data reproduced by said
reproducing unit.
16. The apparatus according to claim 15, further comprises an
operation mode display unit, adapted to display mode information
corresponding to said selecting unit.
17. The apparatus according to claim 16, wherein the mode
information is an SD mode or an HD mode.
18. The apparatus according to claim 15, wherein said display unit
displays information indicative of time and date.
19. The apparatus according to claim 15, wherein said focus control
unit is controlled in accordance with the image size set by said
image size control unit.
20. The apparatus according to claim 15, wherein the compression
mode includes a plurality of compression ratios.
21. The apparatus according to claim 15, wherein the plurality of
image sizes include a plurality of image resolutions.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an image processing
apparatus including an image pickup system and compression
processing means for compressing a photographic image obtained from
the image pickup system.
[0003] 2. Description of the Related Art
[0004] FIG. 1 is a schematic block diagram showing the arrangement
of a conventional example in which a video camera is integrated
with a digital video tape recorder for digitally recording a video
signal.
[0005] In the example shown in FIG. 1, an image pickup device 10 is
provided with a complementary color filter and performs
pseudo-interlaced reading of electric charge stored by field
storage. Specifically, as shown in FIG. 2, the image pickup device
10 is provided with a mosaic color filter made up of filter
elements: white (W), cyan (Cy), yellow (Ye) and green (G). The
image pickup device 10 outputs the added values of two adjacent
upper and lower lines, and a luminance signal processing circuit 12
adds together the values of two adjacent pixels contained in the
output of the image pickup device 10, thereby forming a luminance
signal. A chrominance signal processing circuit 14 obtains
differences between the values of the two adjacent pixels, thereby
forming color-difference signals.
[0006] More specifically, a luminance signal Yn obtained from a
line #n and a luminance signal Yn+1 obtained from a line #(n+1) are
as follows: Yn=(W+Cy)+(G+Ye) Yn+1=(W+Ye)+(G+Cy) and the associated
chrominance signals Cn and Cn+1 are as follows: Cn=(W+Cy)-(G+Ye)
Cn+1=(W+Ye)-(G+Cy)
[0007] If the characteristic of each filter element W is equal to
the sum of R (red), G (green) and B (blue), i.e., R+G+B; the
characteristic of each filter element Cy is equal to B+G; and the
characteristic of each filter element Ye is equal to Ye=R+G, the
following equations are obtained: Yn=Yn+1=2R+4G+2B Cn=2(B-G)
Cn+1=2(R-G)
[0008] As shown in FIG. 2, the line numbers of adjacent upper and
lower lines to be added together are made to differ between an even
field and an odd field, whereby an interlaced signal is obtained.
To perform this addition, the image pickup device 10 needs to be
provided with a photoelectric conversion element having lines the
number of which is equivalent to the number of lines per frame (in
the NTSC system, 525 lines). In the case of the NTSC system, in a
line Lm of the image pickup device 10 shown in FIG. 1, m is
525.
[0009] A luminance signal Y formed by the luminance signal
processing circuit 12 and a chrominance signal C formed by the
chrominance signal processing circuit 14 are stored in an image
memory 16 under the control of a memory control circuit 18. When
image data for one frame are stored in the image memory 16, a
motion detecting circuit 20 discriminates between a moving image
portion and a still image portion. An image compressing circuit 22
compresses the image data supplied from the image memory 16, by
using correlations present in the image. At this time, the image
compressing circuit 22 adaptively switches compression algorithms
between the still image portion and the moving image portion in
accordance with the detection result provided by the motion
detecting circuit 20.
[0010] The compressed image data is applied to an image recording
device 24, and the image recording device 24 records the compressed
image data on a recording medium.
[0011] A system control circuit 26 controls the entire arrangement
in accordance with the operation of a key operation device 28.
[0012] In the above-described arrangement, pseudo-interlaced field
images are compressed and recorded on the recording medium.
[0013] In the conventional example in which compression processing
is performed after field images are combined into a frame image,
there is the problem that if field images of a fast moving subject
are combined into a frame image, the resultant image may be blurred
as shown in FIGS. 3(a) to 3(c). FIG. 3(a) shows an odd field image,
FIG. 3(b) shows the succeeding even field image, and FIG. 3(c)
shows the frame image obtained by combining the odd and even field
images.
[0014] Compression of an image utilizes correlations which appear
in the image in the space and time-axis directions thereof. In
general, a frame picture the vertical line-to-line distance of
which is smaller than that of a field picture contains higher
correlations. For this reason, as described above, the conventional
example adopts the compression method of adaptively switching
compression algorithms between a still image portion and a moving
image portion in a frame image.
[0015] As a result, the conventional example necessarily needs a
motion detecting circuit for detecting a still image portion and a
moving image portion, and, in addition, a substantially high
detection accuracy is needed. This problem makes it difficult to
reduce the size of the circuit.
[0016] As is known to those skilled in the art, since a
conventional camera-integrated type of VTR does not conform to a
plurality of television standards, a plurality of camera-integrated
types of VTRs must be prepared and selectively used according to
individual purposes. With the diversification of broadcasting
systems, it becomes far more necessary to exchange program software
tapes between different nations or to produce software conforming
to multiple broadcasting systems. However, if a plurality of
broadcasting systems are to be handled, a plurality of existing
VTRs are needed, so that practical inconveniences will be
encountered. For this reason, it has been desired to provide a VTR
unit capable of conforming to multiple broadcasting systems.
[0017] As is also known to those skilled in the art, systems for
recording and reproducing a digitized video signal are individually
designed according to necessary image qualities or
recordable/reproducible data rates. However, if system designs
differ in coding sampling frequency which is a primary parameter
for determining image quality, when one system is connected to
another video system, various problems occur.
[0018] Such conventional systems which are separately designed
according to individual required image qualities have the problem
that it is impossible to readily exchange image data between
systems via media.
SUMMARY OF THE INVENTION
[0019] It is, therefore, an object of the present invention to
provide an image processing apparatus capable of solving the
above-described problems.
[0020] To achieve the above object, in accordance with one aspect
of the present invention, there is provided an image processing
apparatus which comprises image pickup means having a plurality of
photographic modes, compression processing means for performing
compression processing of an image pickup signal outputted from the
image pickup means, the compression means having a plurality of
compression modes, and selecting means for selecting one of the
compression modes of the compression processing means in accordance
with a selected one of the photographic modes of the image pickup
means.
[0021] According to the above arrangement, it is possible to fully
utilize the performance of the compression processing means, so
that it is possible to realize a good image quality and a high
compression ratio.
[0022] Another object of the present invention is to provide a
video recording apparatus, a video reproducing apparatus and a
video recording and reproducing apparatus, such as a
multimode-capable camera-integrated type VTR capable of effecting
camera photography, compression signal processing and video
recording according to a plurality of television standards.
[0023] To achieve the above object, in accordance with another
aspect of the present invention, there is provided a video
recording apparatus which comprises image pickup means capable of
conforming to a plurality of television standards, recording means
for compressing data outputted from the image pickup means at a
compression ratio according to a television standard selected from
the plurality of television standards and recording on a recording
medium compressed data and identification information for
identification of the selected television standard, setting means
for setting the selected television standards, and controlling
means for controlling the image pickup means and the recording
means in accordance with a setting of the setting means.
[0024] To achieve the above object, in accordance with another
aspect of the present invention, there is provided a video
reproducing apparatus which comprises reproducing means for
reproducing video data compressed according to a television
standard and identification information for identification of the
television standard from a recording medium on which the video data
and the identification information are recorded, and performing
expansion processing of the video data, and controlling means for
controlling the reproducing means on the basis of the
identification information reproduced from the recording
medium.
[0025] To achieve the above object, in accordance with another
aspect of the present invention, there is provided a video
recording and reproducing apparatus which comprises a system
converter for converting a first video signal conforming to a first
television standard into a second video signal conforming to a
second television standard, recording means for recording the first
or second video signal on a recording medium, switching means for
supplying to the recording means the first video signal or the
second video signal obtained from the system converters reproducing
means for reproducing the first or second video signal from the
recording medium, and signal supplying means for supplying the
first video signal reproduced by the reproducing means to the
system converter.
[0026] According to the first two aspects of the present invention,
with a single camera-integrated type VTR, it is possible to
automatically perform recording processing and reproduction
processing according to a plurality of compression modes which
conform to a plurality of television standards.
[0027] According to the third aspect of the present invention, the
system converter is used during both recording and reproduction so
that it is impossible to perform recording and reproduction of or
provide a monitor output of a video signal according to a desired
television standard.
[0028] In accordance with another aspect of the present invention
which has been made to solve the aforesaid problems, there is
provided a video system which comprises recording means for
recording video information, which is hierarchically coded, while
forming a data recording area on a recording medium in accordance
with a hierarchical structure of the video information and at least
one recording mode of a plurality of recording modes each having a
different recording processing, and reproducing means capable of
setting a reproduction mode according to the at least one recording
mode and the hierarchical structure, or reproducing means capable
of setting a reproduction mode within a range of the hierarchical
structure irrespective of the at least one recording mode.
[0029] According to the above aspect, it is possible to perform
reproduction processing for reproducing recorded data from an
information recording medium which is recorded in one of the
plurality of recording modes, in an arbitrary reproduction mode in
accordance with the conditions of a reproduction side. The recorded
data is reproduced from only a data recording area which
corresponds to a necessary information hierarchy within information
hierarchically recorded on a recorded tape.
[0030] The above and other objects, features and advantages of the
present invention will become apparent from the following detailed
description of preferred embodiments of the present invention,
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a schematic block diagram of the arrangement of a
conventional camera-integrated type digital recording
apparatus;
[0032] FIG. 2 is an explanatory view of the color-filter
arrangement of the image pickup device shown in FIG. 1 and the
manner of reading of electric charge therefrom;
[0033] FIGS. 3(a), 3(b) and 3(c) are explanatory views of an image
blur occurring in a frame image as the result of a combination of
field images;
[0034] FIG. 4 is a schematic block diagram of the arrangement of an
image processing apparatus according to one embodiment of the
present invention;
[0035] FIG. 5 is an explanatory view of the color-filter
arrangement of the image pickup device shown in FIG. 4 and the
manner of reading of electric charge therefrom;
[0036] FIG. 6 is a schematic block diagram of the arrangement of a
camera-integrated type video recording apparatus according to a
second embodiment of the present invention;
[0037] FIG. 7 is a schematic block diagram of one example of the
broadcasting system conversion circuit shown in FIG. 6;
[0038] FIG. 8 is an explanatory, schematic view of a side panel
system for aspect-ratio conversion;
[0039] FIG. 9 is an explanatory, schematic view of a squeeze system
for aspect-ratio conversion;
[0040] FIG. 10 is an explanatory, schematic view of a letter box
system for aspect-ratio conversion;
[0041] FIG. 11 is a comparative table of operating modes;
[0042] FIG. 12 is a schematic block diagram of the arrangement of
the video camera shown in FIG. 6;
[0043] FIG. 13 is a schematic block diagram of the arrangement of
an image compressing circuit in the embodiment shown in FIG. 6;
[0044] FIG. 14 is an explanatory view of a block formed by the
blocking circuit shown in FIG. 13;
[0045] FIG. 15 is an explanatory view of the pixel arrangements of
an even field and an odd field;
[0046] FIG. 16 is an explanatory view of the output of the DCT
circuit shown in FIG. 13;
[0047] FIG. 17 is an explanatory view of a zigzag scan;
[0048] FIG. 18 is a schematic block diagram of the arrangement of
the recording system of a digital video tape recorder;
[0049] FIG. 19 is a schematic view of a recording track pattern on
a magnetic tape;
[0050] FIG. 20 is a view of the data structure of a sub-code;
[0051] FIG. 21 is a schematic block diagram of the arrangement of
the reproducing system of the digital video tape recorder;
[0052] FIG. 22 is a table of the recording characteristics of
individual modes;
[0053] FIG. 23 is a schematic view showing a head for use in an
SD-Low mode;
[0054] FIG. 24 is a schematic view showing tracks for one field in
the SD-Low mode;
[0055] FIG. 25 is a chart showing the timing of head switching
which is performed in the SD-Low mode;
[0056] FIG. 26 is a schematic view showing a head for use in an
SD-High mode;
[0057] FIG. 27 is a schematic view showing tracks for one field in
the SD-High mode;
[0058] FIG. 28 is a chart showing the timing of head switching
which is performed in the SD-High mode;
[0059] FIG. 29 is a schematic view showing a head for use in an HD
mode;
[0060] FIG. 30 is a schematic view showing tracks for one field in
the HD mode;
[0061] FIG. 31 is a chart showing the timing of head switching
which is performed in the HD mode;
[0062] FIG. 32 is a flowchart of mode identification during
reproduction;
[0063] FIG. 33 is a block diagram showing one example of a
broadcasting system converter which serves as an up converter;
[0064] FIG. 34 is a schematic block diagram showing a video
recording and reproducing apparatus according to another embodiment
of the present invention;
[0065] FIG. 35 is a flowchart of a mode setting process according
to another embodiment of the present invention;
[0066] FIG. 36 is an explanatory view of the principle of hill
climbing focus adjustment;
[0067] FIG. 37 is a view showing the relationships between TV forms
and frequency characteristics;
[0068] FIG. 38 is a schematic view of a hierarchical VTR recording
apparatus according to another embodiment of the present
invention;
[0069] FIG. 39 is a conceptual view of the SD recording operation
of the hierarchical VTR recording apparatus;
[0070] FIG. 40 is a conceptual view of the HD recording operation
of the hierarchical VTR recording apparatus;
[0071] FIG. 41 is a schematic block diagram of a hierarchical VTR
reproducing apparatus (HD) according to another embodiment of the
present invention;
[0072] FIG. 42 is a conceptual view of the HD reproducing operation
of the hierarchical VTR reproducing apparatus;
[0073] FIG. 43 is a conceptual view of SD reproduction from an HD
recorded medium to be performed by the hierarchical VTR reproducing
apparatus;
[0074] FIG. 44 is a conceptual view showing the operation a
hierarchical VTR to perform SD reproduction of an SD recording;
[0075] FIG. 45 is a track view showing the SD reproduction of an HD
recording by the hierarchical VTR;
[0076] FIG. 46 is a view showing two kinds of trace angles for HD
and SD in the hierarchical VTR;
[0077] FIG. 47 is a list of the reproducing modes of a hierarchical
VTR for SD signals;
[0078] FIG. 48 is a list of the reproducing modes of a hierarchical
VTR for HD signals; and
[0079] FIG. 49 is a schematic view showing a hierarchical VTR
reproducing apparatus (SD).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0080] The present embodiments are based on the arrangement in
which the present invention is applied to an image processing
apparatus capable of coping with a plurality of photographic modes
or television standards, as well as of performing recording and
reproduction processings on hierarchically coded video signals.
[0081] Each of the embodiments of the present invention will be
described below with reference to the accompanying drawings.
[0082] FIG. 4 is a schematic block diagram showing the arrangement
of an image processing apparatus according to one embodiment of the
present invention. An image pickup device 30 is capable of
selectively performing a field reading operation and a frame
reading operation, and the color-filter arrangement of the image
pickup device 30 is identical to that of the image pickup device 10
shown in FIG. 1. Although the image pickup device 10 is arranged to
output the results of additions of the respective pairs of adjacent
lines, the image pickup device 30 of this embodiment is capable of
independently outputting a charge signal from each pair of adjacent
lines, as shown in FIG. 5. The field reading operation and the
frame reading operation of the image pickup device 30 primarily
differ in reading frequency, and switching between the field
reading operation and the frame reading operation is performed by a
scanning switching circuit 32.
[0083] An even line processing circuit 34 computes charge signals
read from the even lines of the image pickup device 30, with
respect to all the adjacent pixels, thereby forming a luminance
signal Ye of an even field. An odd line processing circuit 36
computes charge signals read from the odd lines of the image pickup
device 30, with respect to all the adjacent pixels, thereby forming
a luminance signal Yo of an odd field. Also, a chrominance signal
processing circuit 38 performs addition of the charge signals read
from the even and odd lines of the image pickup device 30, with
respect to all the adjacent lines, as well as subtraction of the
same charge signals with respect to all the adjacent pixels,
thereby a chrominance signal C.
[0084] Specifically, a luminance signal Yn obtained from a line #n
of the odd field and a luminance signal Yn+1 obtained from a line
#(n+1) are as follows: Yn=W+G Yn+1=Cy+Ye and the associated
chrominance signals Cn and Cn+1 are as follows: Cn=(W+Cy)-(G+Ye)
Cn+1=(W+Ye)-(G+Cy)
[0085] If the characteristic of each filter element W is equal to
the sum of R (red), G (green) and B (blue), i.e., R+G+B; the
characteristic of each filter element Cy is equal to B+G; and the
characteristic of each filter element Ye is equal to Ye=R+G, the
following equations are obtained: Yn=Yn+1=R+2G+B Cn=2(B-G)
Cn+1=2(R-G)
[0086] Regarding the even field as well, luminance signals and
chrominance signals can be obtained through similar
computations.
[0087] Photoelectrically converted signals, which have been
obtained from lines L1 to Lm (m=525 in the NTSC system)
corresponding to horizontal scanning lines which constitute a
television picture, are applied to the even line processing circuit
34, the odd line processing circuit 36 and the chrominance signal
processing circuit 38, and the luminance signal Ye and the
luminance signal Yo as well as the chrominance signal C which is
common to the signals Ye and Yo are formed.
[0088] A frame photographic image outputted from the image pickup
device 30 is stored in an image memory 42 in the following manner.
The image pickup device 30 outputs the photoelectrically converted
signals of all the lines in the order of the lines, or
simultaneously outputs the respective photoelectrically converted
signals of the even lines and the odd lines in line order. Since a
switch 44 is open, the luminance signal Ye formed by the even line
processing circuit 34 passes through an adder 40 without being
subject to addition, and is applied to the image memory 42. The
luminance signal Yo formed by the odd line processing circuit 36
and the chrominance signal C formed by the chrominance signal
processing circuit 38 are also applied to the image memory 42. The
image memory 42 stores the luminance signals Ye and Yo and the
chrominance signal C under the control of a memory control circuit
46. Thus, a frame image obtained by one exposure cycle is stored in
the image memory 42. The above-described operation is hereinafter
referred to as the "frame image pickup mode".
[0089] The operation of combining field photographic images
obtained by the image pickup device 30 to form a frame image and
storing the resultant frame image in the image memory 42 is
performed in the following manner. The image pickup device 30
outputs the photoelectrically converted signals of all the lines in
the order of the lines, or simultaneously outputs the respective
photoelectrically converted signals of the even lines and the odd
lines in line order. In this reading stage, image data for an odd
field is first stored in the image memory 42. Specifically, the
image memory 42 stores the luminance signal Yo of the odd field
which is formed by the odd line processing circuit 36 as well as
the chrominance signal C formed by the chrominance signal
processing circuit 38.
[0090] During the next field, the switch 44 is closed and the image
memory 42 is made to operate in a read modify write mode, thereby
feeding the stored luminance signal Yo back to the adder 40 through
the switch 44. Similarly to the aforesaid odd field, the image
pickup device 30 outputs the photoelectrically converted signals of
all the lines in the order of the lines, or simultaneously outputs
the respective photoelectrically converted signals of the even
lines and the odd lines in line order. In this reading stage, the
even line processing circuit 34 and the chrominance signal
processing circuit 38 operate, and the adder 40 adds the luminance
signal Yo fed back from the image memory 42 to the luminance signal
Ye formed by the even line processing circuit 34. Thus, it is
possible to obtain a result similar to the result of two-line
addition described previously in connection with the conventional
example. The image memory 42 sequentially stores the output of the
adder 40 and the output of the chrominance signal processing
circuit 38 into predetermined memory locations. Thus, a frame image
in which the field images obtained through two exposure cycles are
combined is stored in the image memory 42. The above-described
operation is referred to as the "field image pickup mode".
[0091] When the image data for one frame is stored in the image
memory 42, the image compressing circuit 48 compresses the image
data stored in the image memory 42 in a compression mode according
to a control signal supplied from a system control circuit 52. For
example, according to which of the frame image pickup mode and the
field image pickup mode is active, a block to be formed by block
coding such as DCT (discrete cosine transform), which block is a
main unit in image compression processing, is determined as a
field-based block or a frame-based block.
[0092] The compressed image data outputted from the image
compressing circuit 48 is applied to an image recording device 50,
and the image recording device 50 records the compressed image data
on a recording medium.
[0093] The system control circuit 52 controls the entire apparatus
in accordance with the operation of a key operation device 54.
[0094] As a matter of course, it is also possible to select a
compression system from among various compression coding systems
other than DCT. For example, if a DPCM system which is one kind of
predictive coding system is employed, in the case of the field
image pickup mode in which a higher correlation appears in a
horizontal direction than in a vertical direction, compression is
performed by a horizontal DPCM system of performing a differential
computation in the horizontal direction, while, in the case of the
frame image pickup mode in which a higher correlation appears in a
vertical direction than in a horizontal direction, compression is
performed by a vertical DPCM system of performing a differential
computation in the vertical direction.
[0095] In the above-described embodiment, switching between
field-based image compression and block-based image compression is
performed according to which of the field image pickup mode and the
frame image pickup mode has been selected. However, as a matter of
course, it is also possible to adopt an arrangement capable of
selecting the field image pickup mode or the frame image pickup
mode in accordance with whether the field-based image compression
or the frame-based image compression has been selected. In other
words, it is possible to reduce a degradation of image quality by
linking the field image pickup mode or the frame image pickup mode
with the field-based image compression or the frame-based image
compression.
[0096] Another embodiment of the present invention will be
described below in which the present invention is applied to a
camera-integrated type video recording apparatus which is
compatible to an existing broadcasting system (for example, the
NTSC system (SD)) and a high-definition television system (for
example, a "high-vision" system (HD)) and of performing camera
photography, compression processing and recording which is intended
to two layers of image structures (SD and HD) each having a
different image-quality design. FIG. 6 is a schematic block diagram
of the arrangement of the entire apparatus.
[0097] Referring to FIG. 6, an HDTV camera 60 is arranged to output
a high-definition television signal, i.e., an HD signal. According
to a television studio standard, the number of effective pixels per
picked-up image is 1,920 pixels in the horizontal direction and
1,035 pixels in the vertical direction, and the sampling frequency
is 75.3 MHz. The output of the camera 60 enters two different
paths. The signal which has entered one path is applied to an image
pickup mode selecting circuit 64 via a broadcasting system
conversion circuit 62, while the signal which has entered the other
paths is directly applied to the image pickup mode selecting
circuit 64.
[0098] The broadcasting system conversion circuit 62 is a down
converter for converting an HD signal into a signal conforming to
any of the NTSC, PAL and SECAM systems which are standard
broadcasting systems (hereinafter referred to as the "SD
system").
[0099] One example of the broadcasting system conversion circuit 62
for converting an HD signal into an NTSC signal is shown in FIG. 7.
Since the HD signal has an aspect ratio of 16:9 and the SD signal
has an aspect ratio of 4:3, an aspect ratio conversion circuit 100
converts the 16:9 aspect ratio into the 4:3 aspect ratio.
[0100] Specifically, it is possible to select a desired system from
among a side panel system in which the right and left end portions
of a high-vision image are omitted (refer to FIG. 8), a squeeze
system (or a full-display system) in which a high-vision image is
compressed in the horizontal direction (refer to FIG. 9), and a
letter box system in which an image of 16:9 aspect ratio is
displayed in a picture of 4:3 aspect ratio (refer to FIG. 10). In
the case of the letter box system, although empty spaces are formed
in the top and bottom portions of a picture, they are displayed in
black. If the HD signal is to be converted into the NTSC system,
the side panel system or the squeeze system is suitable, while the
letter box system is suited to a case where it is desired to fully
utilize the photographic field angle of the HD camera 60.
[0101] The HD signal and the SD signal greatly differ in the number
of horizontal scanning lines. A number-of-scanning-lines conversion
circuit 102 converts the number of horizontal scanning lines of the
HD output of the aspect ratio conversion circuit 100 into the
number of horizontal scanning lines conforming to the SD system.
For example, signals for the required horizontal scanning lines are
formed by a vertical interpolation filter.
[0102] A field frequency conversion circuit 104 converts the field
frequency of the output of the number-of-scanning-lines conversion
circuit 102 (60 HZ in the case of the high-definition signal) into
a field frequency conforming to the SD system (59.94 Hz in the case
of the NTSC system). This frequency conversion can be executed at
real time by a time-base corrector having a function similar to a
frame synchronizer.
[0103] In a generally used frame synchronizer, in the case of a
capacity of one frame memory, one frame cap occurs at intervals of
approximately 33 seconds and causes an unnatural discontinuity in a
moving image. In contrast, motion-adaptive type field frequency
conversion detects motions and scene changes by using a frame
difference signal, and performs frame skipping if the following
four conditions are satisfied:
[0104] 1) an image signal indicates a still image;
[0105] 2) a scene change has occurred;
[0106] 3) a moving-image area is comparatively small; and
[0107] 4) a frame buffer memory is full.
[0108] An NTSC encoder 106 converts the output of the field
frequency conversion circuit 104 into a television signal
conforming to the NTSC system.
[0109] In the present embodiment, in the case of the SD system as
well, it is possible to select a high image quality mode for
business use (horizontal resolution: approximately 450 lines) and a
standard image quality mode for home use (horizontal resolution:
approximately 230 lines). The former mode is hereinafter referred
to as the "SD-High mode", while the latter mode is hereinafter
referred to as the "SD-Low mode". A mode for recording the HD
signal is hereinafter referred to as the "HD mode". An operator can
selectively set the HD mode, the SD-High mode or the SD-Low mode by
means of an operation panel 92, and a system control circuit 90
controls the image pickup mode selecting circuit 64 in accordance
with the mode set by the operator. The image pickup mode selecting
circuit 64 selects the HD signal output of the camera 60 in the
case of the HD mode or the output of the broadcasting system
conversion circuit 62 in the case of the SD-High mode or the SD-Low
mode.
[0110] The signal selected by the image pickup mode selecting
circuit 64 is applied to a compression circuit 66. The compression
circuit 66 is provided with a plurality of compression modes (in
the shown example, a mode #1 and a mode #2) so that a compression
ratio and a compression coding system can be individually selected.
The compression ratio is selected from among, for example, 1/4,
1/8, 1/16 and 1/32. The compression coding system is selected from,
for example, DCT, DPCM, Hadamard transform and ADRC. In the
arrangement shown in FIG. 6, for example, DCT and DPCM may be
allocated to the compression mode #1 and the compression mode #2,
respectively, or the compression ratio may be varied under a single
compression coding system.
[0111] The compression circuit 66 compresses the output of the
image pickup mode selecting circuit 64 in the compression mode #1
as well as in the compression mode #2. The data compressed in the
compression mode #1 and the compression mode #2 are both applied to
a compression mode selecting circuit 68. The compression mode
selecting circuit 68 selects either one of the data compressed in
the compression mode #1 and the data compressed in the compression
mode #2, in accordance with a control signal supplied from the
system control circuit 90, and applies the selected compressed data
to a recording processing circuit 70.
[0112] The modes to be selected by the image pickup mode selecting
circuit 64 and the compression mode selecting circuit 68 are
closely related to factors, such as a recording time or image
quality to be selected for a recording system and the quality of an
image to be picked up by the camera 60 or a mode set for the camera
60. The modes are automatically determined in association with such
factors.
[0113] According to a relationship with a recording system which
will be described later, it is desirable that the data rates of
images compressed in the respective compression modes have a
relationship represented by an integer ratio, for example, 50 Mbps
in the HD mode, 25 Mbps in the SD-High mode and 12.5 Mbps in the
SD-Low mode, as shown in FIG. 22.
[0114] A recording processing circuit 70 applies recording
processing, such as modulation, to the compressed data supplied
from the compression mode selecting circuit 68, divides the
processed data into two channels, and outputs the divided data to
the respective channels. Recording amplifiers 72a and 72b amplify
the respective outputs of the recording processing circuit 70. A
rotary drum 74 is provided with two pairs of heads 76a, 76b and
78a, 78b. The outputs of the recording amplifiers 72a and 72b are
respectively recorded on a magnetic tape 80 by the heads 76a, 76b
and 78a, 78b. The width of each track formed on the magnetic tape
80 is the same for any of the HD mode, the SD-High mode and the
SD-Low mode.
[0115] A servo circuit 82 causes a drum motor 84 to rotate the
rotary drum 74 at a predetermined rotational speed, and also causes
a capstan motor 86 to rotate a capstan 88, thereby causing the
magnetic tape 80 to run at a predetermined speed. The system
control circuit 90 supplies to the servo circuit 82 a target value
based on an operation mode according to an operation instruction
inputted through the operation panel 92.
[0116] FIG. 11 shows the relationships between the modes selected
through the operation panel 92 and the image pickup systems, the
compression ratios and the recording data rates.
[0117] The camera 60 shown in FIG. 6 will be described in detail
with reference to FIG. 12. A photographic lens unit 110 includes a
focusing lens 110a for adjusting its focal length and a zooming
lens 110b for varying its magnification, and focuses an optical
image of a subject on the photoelectric conversion face of an image
pickup device 114 via an iris 112. A predetermined color filter 116
is attached to the photoelectric conversion face of the image
pickup device 114.
[0118] The image pickup device 114 operates in accordance with a
clock supplied from a clock generating circuit 118, and outputs a
charge signal. The output of the image pickup device 114 is
noise-reduced by a CDS circuit 120 and is then gain-controlled by
an AGC circuit 122. The output of the AGC circuit 122 is applied to
an exposure control circuit 124, a focus control circuit 126, a
white balance adjustment circuit 128 and a color processing circuit
130.
[0119] A driving circuit 132a and a motor 132b drive the focusing
lens 110a along the optical axis, a driving circuit 134a and a
motor 134b drive the zooming lens 110b along the optical axis, and
a driving circuit 136a and a motor 136b drive the iris 112 to cause
it to open and close.
[0120] A system control circuit 138 controls the gain of the AGC
circuit 122 in accordance with the output of the exposure control
circuit 124, and also controls the degree of opening of the iris
112 by means of the driving circuit 136a and the motor 136b. The
system control circuit 138 adjusts the position of the focusing
lens 110a along the optical axis by means of the driving circuit
132a and the motor 132b in accordance with the output of the focus
control circuit 126, thereby placing the photographic lens unit 110
into an in-focus state.
[0121] The white balance adjustment circuit 128 forms a control
signal for white balance adjustment, and the system control circuit
138 controls the color processing circuit 130 in accordance with
the output of the white balance adjustment circuit 128. The color
processing circuit 130 generates a white-balanced luminance signal
Y as well as color-difference signals R-Y and B-Y from the output
of the AGC circuit 122. A process circuit 140 converts into RGB
signals the luminance signal Y and the color-difference signals R-Y
and B-Y outputted from the color processing circuit 130, and an
encoder 142 generates a composite signal from the output of the
process circuit 140. The encoder 142 also outputs video signals in
Y/C separation form.
[0122] The outputs of the color processing circuit 130 and the
outputs of the process circuit 140 may of course be outputted to
the outside as component outputs.
[0123] A display generating circuit 144 generates display signals
indicative of operation mode, time and date and the like under the
control of the system control circuit 138, and an adder 146 adds
the output of the display generating circuit 144 to the composite
output of the encoder 142 and applies a signal indicative of the
addition result to an electronic viewfinder 148. Thus, a
photographer can view various kinds of information together with a
subject to be photographed, on the screen of the electronic
viewfinder 148. Further, since a composite signal is inputted to
the electronic viewfinder 148 from a reproducing system which will
be described later, it is possible to view a reproduced image.
[0124] The photographer also can set photographic conditions, such
as photographic mode, photographic magnification and exposure, by
operating an operation key 150.
[0125] If photographic image information is digitally processed in
the camera shown in FIG. 12, each output signal may of course be
outputted in digital form. If analog outputs are needed, a D/A
converter and a band-limiting low-pass filter may be provided at
suitable locations.
[0126] The compression processing performed in the compression
circuit 66 shown in FIG. 6 will be described below in brief.
Compression of an image is to reduce the amount of data by removing
the redundancy of the image. Compression of a still image utilizes
the spatial redundancy of the image. Compression of a moving image
utilizes its temporal redundancy in addition to its spatial
redundancy, but the basic principles are based on still image
compression techniques.
[0127] The element techniques of moving-image compression which
conforms to, for example, the MPEG (Moving Picture Expert Group)
standard, are DCT (discrete cosine transform) processing,
quantization processing, coding processing and motion adaptation
processing. Expansion can be regarded as the inverse process of
compression. The DCT (discrete cosine transform) processing, the
quantization processing and the coding processing are common to
both the moving-image compression and still-image compression.
These techniques will be described below in brief in that
order.
[0128] DCT converts spatial coordinates into frequencies. As the
pre-processing of compression, an input picture is blocked into a
pixel group of approximately 8.times.8 pixels. Multiplication
processing using DCT coefficients is performed in units of blocks,
whereby space data are converted into frequency data. Although the
amount of data is not reduced by DCT alone, it is possible to
concentrate data which is widely dispersed in the picture. In other
words, an image has a general tendency for more energy to
concentrate on a lower spatial frequency side, and DCT performs the
function of increasing a compression ratio for substantial
compression processing to be executed at the succeeding stages.
[0129] The quantization processing rounds off the word lengths of
coefficients which have been converted into frequencies by the DCT
processing, thereby reducing the amount of data. For example, a
data coefficient indicative of each frequency component produced by
DCT is divided by an appropriate value, and the figures below the
decimal point of the resultant value are omitted. By omitting the
figures below the decimal point, it is possible to reduce the
number of bits which are required to represent each coefficient
data, whereby the total amount of data can be reduced. By setting a
divisor for each frequency component, it is possible to increase
the compression ratio while retaining the required image
quality.
[0130] The coding processing assigns to each data a length code
corresponding to the occurrence frequency of the data. First, a
zigzag scan of the quantized data is performed to convert a
two-dimensional data array into a unidimensional data string. The
two-dimensional data array is scanned in a zigzag manner from a DC
component toward horizontal and vertical higher-frequency
components, whereby the data is rearranged. By run length coding,
the same numbers (mainly, zeros) which continuously occur are
replaced with one code which collectively represents such
continuous occurrence. If the data which appear after a particular
location are all zeros, an end code is assigned to the data. This
code indicates that if it is detected in a block, the transfer of
data from the block is brought to an end, and realizes a great,
data reduction effect.
[0131] By assigning codes of fewer bits to numbers having higher
occurrence frequencies, the substantial total number of coding bits
can be reduced.
[0132] The motion adaptation processing adds the technique of
detecting and predicting a motion to still-image compression. The
element techniques includes motion detection, motion predictive
compensation and interlacing coding. The motion adaptation
processing will be described below with illustrative reference to
the case of compression of a moving image conforming to a
television broadcasting standard.
[0133] In the motion detection, image data is delayed by a time
which corresponds to an integer multiple of a field (or frame)
period, as by a frame memory, and two field (frame) pictures are
compared in a time-axis direction, thereby detecting a motion. As
well-known motion detecting methods, there are a method of
obtaining the amount of motion as the absolute value of the
difference in luminance data between pictures and a method of
computing the travel of a two-dimensional coordinate point having a
highest correlation, thereby detecting a motion vector.
[0134] The motion predictive compensation predicts a motion of an
image by the detected motion vector and transmits only the
difference between a predicted image and an actual image as
compensation data. Accordingly, it is possible to reduce the amount
of information to be transferred. Specifically, it is possible to
reduce prediction errors in the case of images, such as an image
which contains a large still-image portion and moves to a small
extent, an image which moves moderately and an image which is
rectilinearly travelling. Accordingly, a high compression effect
can be achieved.
[0135] The interlacing coding forms a pixel block for compression
processing in units of fields. A television signal, such as an NTSC
television signal, has an interlaced structure in which the
scanning lines of odd and even fields are alternately disposed. An
odd field made up of 262.5 odd lines and an even field made up of
262.5 even lines are paired to form a frame picture made up of 525
lines.
[0136] If an odd field and an even field are simply combined when
the amount of motion of a subject in a picture is large, a frame
image blurs and is visually extremely impaired. In a blurred
portion of the picture, a vertical spatial correlation is lowered,
so that no high compression ratio can be achieved by compression
coding processing. If the amount of motion is small, this problems
does not occur.
[0137] For this reason, if the amount of motion is small, a pixel
block for compression processing is formed within a frame picture,
while if the amount of motion is greater than a predetermined
amount, a pixel block for compression processing is formed within a
field picture.
[0138] FIG. 13 is a schematic block diagram showing the arrangement
of an image compressing circuit which adopts the above-described
moving image compression processing techniques. Referring to FIG.
13, an SD or HD signal outputted from the image pickup mode
selecting circuit 64 shown in FIG. 6 is inputted through an input
terminal 200. The video signal inputted through the input terminal
200 is inputted to an input buffer 202 and a motion detecting
circuit 204. The input buffer 202 functions as 1-frame-period delay
means, and its output is applied to a blocking circuit 206 and the
motion detecting circuit 204.
[0139] The motion detecting circuit 204 performs the
above-described comparison computation on the video signal supplied
from the input terminal 200 and the video signal outputted from the
input buffer 202, thereby detecting a motion vector. The motion
detecting circuit 204 outputs information indicative of the amount
and direction of the motion to a system control circuit 220. On the
basis of the motion vector information, the system control circuit
220 determines whether compression processing is to be performed in
units of fields or in units of frames, and applies the resultant
field/frame selection information to the blocking circuit 206.
[0140] The blocking circuit 206 blocks the output image of the
input buffer 202 into 8 pixels.times.8 pixels as shown in FIG. 14,
in the units of fields or frames according to the field/frame
selection signal supplied from the system control circuit 220. FIG.
15 shows the pixel arrangements of odd and even fields within one
frame.
[0141] A DCT circuit 208 performs discrete cosine transform of the
blocked pixel data supplied from the blocking circuit 206. By this
discrete cosine transform, the image data is converted into
coefficient data which is represented as a block of 8
pixels.times.8 pixels in a frequency space as shown in FIG. 16. As
the general nature of an image, a DC coefficient and
lower-frequency AC components have larger values, while
higher-frequency AC components have values close to zero.
[0142] The output of the DCT circuit 208 is applied to a quantizing
circuit 210 and a coefficient setting circuit 212. The coefficient
setting circuit 212 sets a quantizing coefficient for the
quantizing circuit 210 in accordance with a control signal supplied
from the system control circuit 220 and the output of the DCT
circuit 208. The quantizing circuit 210 quantizes the output of the
DCT circuit 208 with the quantizing coefficient set by the
coefficient setting circuit 212. Specifically, data coefficients
for the individual frequency components are divided by adequate
divisors, and the figures below the decimal points of the
respective results are omitted to reduce the number of bits.
Incidentally, the divisors may differ among the individual
frequency components.
[0143] A coding circuit 214 first performs a zigzag scan of the
output of the quantizing circuit 210 in the zigzag manner shown in
FIG. 17 from a DC component toward horizontal and vertical
higher-frequency components as shown in FIG. 17, thereby
unidimensionally rearranging the data. After then, the coding
circuit 214 replaces continuing zeros with a predetermined code
indicative of the number of the continuing zeros by run length
coding. As described previously, if all the data which appear after
a particular location are zeros, the coding circuit 214 assigns an
end code to the data. The coding circuit 214 also assigns a short
code to data the occurrence frequency of which is high, by variable
length coding. Thus, the amount of data can be greatly reduced.
[0144] An amount-of-data calculating circuit 218 calculates the
amount of the coded data generated by the coding circuit 214 and
supplies the result to the system control circuit 220. The system
control circuit 220 causes the coefficient setting circuit 212 to
generate a quantizing coefficient which is selected so that the
amount of coded data to be generated by the coding circuit 214
becomes a predetermined value.
[0145] The output of the coding circuit 214 is supplied to an
output buffer 216. The output buffer 216 supplies the output of the
coding circuit 214 to a rear-stage circuit at a data rate. The
output buffer 216 also supplies information indicative of its
internal data occupation ratio to the system control circuit 220.
The system control circuit 220 controls the coefficient setting
circuit 212 so that this occupation ratio becomes stable in the
neighborhood of a predetermined value in order to prevent an
overflow or a data shortage from occurring in the output buffer
216. Specifically, if the data occupation ratio is high, the system
control circuit 220 causes the coefficient setting circuit 212 to
set a large coefficient (divisor), whereas if the data occupation
ratio is low, the system control circuit 220 causes the coefficient
setting circuit 212 to set a small coefficient (divisor).
[0146] In the arrangement shown in FIG. 13, the system control
circuit 220 controls the coefficient setting circuit 212 in
accordance with the amount of coded data generated by the coding
circuit 214 (the output of the amount-of-data calculating circuit
218) and the data occupation ratio of the output buffer 216. An
operator can instruct, through a mode selecting member 222, the
system control circuit 220 to perform switching among the
compression ratios (target values), the compression systems and the
like. Of course, the system control circuit 220 can adaptively
control the compression ratios (target values), the compression
systems and the like in accordance with the result of the detection
of a motion of an image and an operation mode set by the mode
selecting member 222, whereby it is possible to efficiently
compress a moving image. As a matter of course, by changing the
coefficient to be set by the coefficient setting circuit 212, it is
also possible to vary the compression ratio.
[0147] The recording system for recording a signal supplied from
the camera system of FIG. 12 will be described below in detail.
FIG. 18 is a detailed block diagram showing the arrangement of the
recording system. In the shown arrangement, a system control
circuit 336 is substantially identical to the system control
circuit 138 of the camera system.
[0148] An A/D converter 300 converts the luminance signal Y into a
digital signal, while an A/D converter 302 converts the chrominance
signal C into a digital signal. The luminance signal Y and the
chrominance signal C are those supplied from the camera system
described previously with reference to FIG. 12. Of course, if
digital processing is already performed in the camera system,
neither of the A/D converters 300 and 302 is needed.
[0149] A multiplexer 306 of a video data processing circuit 304
multiplexes the outputs of the A/D converters 300 and 302 and
outputs the multiplexed data to an amount-of-information
compressing circuit 308. The amount-of-information compressing
circuit 308 compresses the multiplexed data by using a compression
system and a compression ratio according to mode information
supplied from the system control circuit 336. The
amount-of-information compressing circuit 308 is substantially
identical to the circuit described above with reference to FIG. 13.
Of course, it is also possible to adopt a circuit arrangement for
individually compressing the amounts of information of luminance
data and chrominance data without multiplexing these data in the
multiplexer 306.
[0150] A shuffling circuit 310 rearranges the output data string of
the amount-of-information compressing circuit 308 in accordance
with appropriate rules, thereby preventing a transmission error
from easily occurring in the data string. This shuffling operation
also has the effect of making uniform the uneven distribution of
the amount of information in a picture which is based on the
presence of dense and sparse portions in the picture. The execution
of the shuffling operation at a stage preceding the compression of
the amount of information is convenient for variable length coding,
such as run length coding.
[0151] An ID adding circuit 312 adds identification (ID)
information for restoring the data shuffled by the shuffling
circuit 310. This identification information also contains mode
information indicative of modes used for recording (the kind of
compression system and the like), and is used as auxiliary
information for expansion processing during reproduction. An ECC
adding circuit 314 adds an error-correcting code to the output data
of the ID adding circuit 312.
[0152] The video data subjected to the above-described processing
in the video data processing circuit 304 is distributed into
two-channels by a data distributing circuit 316.
[0153] An A/D converter 318 converts the L-channel signal of a
stereophonic audio signal into a digital signal, while an A/D
converter 320 converts the R-channel signal into a digital signal.
A multiplexer 324 of an audio data processing circuit 322
multiplexes the outputs of the A/D converters 318 and 320 and
outputs the multiplexed data to an amount-of-information
compressing circuit 326. The amount-of-information compressing
circuit 326 compresses the multiplexed data by using a compression
system and a compression ratio according to mode information
supplied from the system control circuit 336.
[0154] If the recording rate of video data is large, as in the case
of an HD signal, audio information may also be recorded on a
recording medium without compression.
[0155] A shuffling circuit 328 rearranges the output data string of
the amount-of-information compressing circuit 326 in accordance
with appropriate rules, thereby preventing a transmission error
from easily occurring in the data string. An ID adding circuit 330
adds identification (ID) information for restoring the data
shuffled by the shuffling circuit 328. This identification
information also contains mode information indicative of modes used
for recording (the kind of compression system and the like), and is
used as auxiliary information for expansion processing during
reproduction. An ECC adding circuit 332 adds an error-correcting
code to the output data of the ID adding circuit 330.
[0156] The audio data subjected to the above-described processing
in the audio data processing circuit 322 is distributed into two
channels by a data distributing circuit 334.
[0157] A pilot generating circuit 338 generates a pilot signal for
tracking servo, and a sub-code generating circuit 340 generates
auxiliary data to be recorded simultaneously with the video and
audio data. Such auxiliary data contains, for example, an address
code for searching for a position on a magnetic tape and the
indexes of a program to be recorded.
[0158] A multiplexer 342 multiplexes one of the channel outputs of
each of the data distributing circuits 316 and 334, the pilot
signal outputted from the pilot generating circuit 338, and the
sub-code data generated by the sub-code generating circuit 340. A
multiplexer 344 multiplexes the other channel output of each of the
data distributing circuits 316 and 334, the pilot signal outputted
from the pilot generating circuit 338, and the sub-code data
generated by the sub-code generating circuit 340. In the case of
time-base multiplexing, the multiplexing of the pilot signal may be
performed in accordance with an area division ATF system which is
well known in the field of digital audio tape recorders.
[0159] Digital modulating circuits 346 and 348 digitally modulate
the respective outputs of the multiplexers 342 and 344 by means of,
for example, 8-10 conversion and an NRZI method.
[0160] The recording system according to the present embodiment is
provided with two pairs of magnetic heads. A head switching circuit
350 switches the output of the modulating circuit 346 between
recording amplifiers 354 and 356 in accordance with a control
signal supplied from a servo circuit 378. A head switching circuit
352 switches the output of the modulating circuit 348 between
recording amplifiers 358 and 360 in accordance with a control
signal supplied from the servo circuit 378. The outputs of the
recording amplifiers 354, 356, 358 and 360 are respectively applied
to magnetic heads 364a, 364c, 364b and 364d of a rotary drum 362,
whereby they are recorded on a magnetic tape 366. FIG. 19 shows one
example of the track pattern of the magnetic tape 366. Each of the
tracks contains a pilot signal P, audio data A, sub-code S and
video data V. FIG. 20 shows the detailed data structure of the
sub-code S.
[0161] The servo circuit 378 controls the rotation of the rotary
drum 362 and the running of the magnetic tape 366 as well as the
head switching operations of the head switching circuits 350 and
352. Specifically, a rotation detector (FG) 376 for detecting the
rotation of a capstan motor 374 for causing the magnetic tape 366
to run is connected to the capstan motor 374, and the servo circuit
378 controls, according to the output of the rotation detector (FG)
376, the capstan motor 374 to cause it to rotate at a predetermined
rotational speed.
[0162] Also, a drum motor 368 rotates the rotary drum 362, a
rotation detector (FG) 370 detects the rotational speed of the drum
motor 368, and a rotational phase detector (PG) 372 detects the
rotational phase of the rotary drum 362. The servo circuit 378
drives, according to the outputs of the rotation detector (FG) 370
and the rotational phase detector (PG) 372, the drum motor 368 to
cause the rotary drum 362 to rotate at a predetermined rotational
speed. The servo circuit 378 also controls the head switching
operations of the head switching circuits 350 and 352 in accordance
with the output of the rotational phase detector (PG) 372.
[0163] The system control circuit 336 controls the entire recording
system in accordance with an instruction inputted through an
operation panel (not shown) and on the basis of the operating state
of each part.
[0164] The functions of the system control circuit 336 and the
servo circuit 378 are realized by one microcomputer chip.
[0165] The reproducing system will be described below in detail
with reference to FIG. 21. In FIG. 21, identical reference numerals
are used to denote constituent elements identical to those shown in
FIG. 18. Specifically, in a manner similar to the recording
operation, the servo circuit 378 causes the magnetic tape 366 to
run at a predetermined speed by means of the capstan motor 374 as
well as causes the rotary drum 362 to rotate at a predetermined
rotational speed and in a predetermined rotational phase by means
of the capstan motor 374.
[0166] The outputs of the magnetic heads 364a, 364c, 364b and 364d
are respectively amplified by reproducing amplifiers 380, 382, 384
and 386, and the outputs of the reproducing amplifiers 380, 382 and
384, 386 are respectively applied to head switching circuits 388
and 390. In accordance with control signals supplied from the servo
circuit 378, the head switching circuit 388 switches the outputs of
the reproducing amplifiers 380 and 382 therebetween, while the head
switching circuit 390 switches the outputs of the reproducing
amplifiers 384 and 386 therebetween. Demodulating circuits 392 and
394 respectively digitally demodulate the outputs of the head
switching circuits 388 and 390 by a redundancy detecting method,
such as a differential detecting method, an integral detecting
method or Viterbi decoding, and output two-level signals. Each of
the outputs of the demodulating circuits 392 and 394 is made of
information which includes video information, audio information, a
pilot signal and sub-code information in a time division
multiplexed state.
[0167] Signal distributing circuits 396 and 398 supply the
respective outputs of the demodulating circuits 392 and 394 to
predetermined circuits: that is to say, the video information is
supplied to a data integrating circuit 406, the audio information
is supplied to a data integrating circuit 424, the pilot signals
are supplied to a pilot detecting circuit 400, and the sub-code
information is supplied to a sub-code detecting circuit 402.
[0168] The pilot detecting circuit 400 detects as an error signal
the time difference between the pilot signal and a timing reference
signal corresponding to an off-track amount relative to the right
and left tracks, and supplies the error signal to the servo circuit
378. The servo circuit 378 adjusts a tape transporting speed in
accordance with the error signal. The error signal can also be used
as auxiliary information for identification of a recording
mode.
[0169] A sub-code detecting circuit 402 decodes the content of the
sub-code from each of the S outputs of the signal distributing
circuits 396 and 398, and supplies the result to a system control
circuit 404. The system control circuit 404 controls each part in
accordance with the content of the reproduced sub-code.
[0170] The data integrating circuit 406 integrates the video
information supplied from the signal distributing circuits 396 and
398 via two lines, and outputs the integrated video information to
a video data reproducing circuit 408.
[0171] In the video data reproducing circuit 408, an error
correcting circuit 410 corrects an error which has occurred during
recording or reproduction. If the error cannot be corrected, the
error correcting circuit 410 performs correction of the error by
using interpolation. An ID detecting circuit 412 detects the ID
added by the ID adding circuit 312 during recording, and supplies
the ID to the system control circuit 404. A de-shuffling circuit
414 restores the data string rearranged by the shuffling circuit
310, and an amount-of-information expanding circuit 416 expands the
data compressed by the amount-of-information compressing circuit
308, in accordance with the mode information supplied from the
system control circuit 404, thereby restoring the original image
data. A data separating circuit 418 separates the original image
data into luminance data and chrominance data and supplies the
respective data to D/A converters 420 and 422. The data separating
circuit 418 also outputs the digital image data to the outside.
[0172] The D/A converter 420 converts the luminance data into an
analog signal, while the D/A converter 422 converts the chrominance
data into an analog chrominance signal. The analog signals are both
outputted to the outside, and are also converted into a composite
signal, which is inputted to the adder 146 of FIG. 12. An operator
can view a reproduced image in the electronic viewfinder 148.
[0173] The data integrating circuit 424 integrates the audio
information supplied from the signal distributing circuits 396 and
398 via two lines, and outputs the integrated audio information to
an audio data reproducing circuit 426.
[0174] In the audio data reproducing circuit 426, an error
correcting circuit 428 corrects an error which has occurred during
recording or reproduction. If the error cannot be corrected, the
error correcting circuit 428 performs correction of the error by
using interpolation. An ID detecting circuit 430 detects the ID
added by the ID adding circuit 330 during recording, and supplies
the ID to the system control circuit 404. A de-shuffling circuit
432 restores the data string rearranged by the shuffling circuit
328, and an amount-of-information expanding circuit 434 expands the
data compressed by the amount-of-information compressing circuit
326, in accordance with the mode information supplied from the
system control circuit 404, thereby restoring the original audio
data. A data separating circuit 436 separates the original audio
data into L-channel audio data and R-channel audio data and
supplies the respective data to D/A converters 438 and 440. The
data separating circuit 436 can also output the digital audio data
to the outside.
[0175] The D/A converter 438 converts the L-channel audio data into
an analog signal, while the D/A converter 440 converts the
R-channel audio data into an analog signal. The analog signals are
both outputted to the outside.
[0176] As described previously, the present embodiment is provided
with the three modes: the HD mode, the SD-High mode and the SD-Low
mode. Since recording track patterns differ among the three modes,
mode identification information is recorded in sub-code areas so
that reproduction from tracks can be correctly performed in the
case of any of the three modes. The recording track patterns and
mode identification methods for the respective modes will be
described below. FIG. 22 shows magnetic tape running speeds, the
number of tracks per field and compression ratios for the
respective modes.
[0177] The SD-Low mode serves as a long-time recording mode for the
SD signal. Out of the four magnetic heads Ha, Hb, Hc and Hd shown
in FIG. 23, only the magnetic heads Ha and Hb are used, and five
tracks per field are formed as shown in FIG. 24. FIG. 25 shows the
timing of head switching. Recording current is alternately applied
to the magnetic heads Ha and Hb each time a drum PG pulse goes high
while a rotary drum is being rotated at 150 rps.
[0178] In the SD-High mode, out of the four magnetic heads Ha, Hb,
Hc and Hd shown in FIG. 26, only the magnetic heads Ha and Hc are
used, and ten tracks per field are formed as shown in FIG. 27. FIG.
28 shows the timing of head switching. While the rotary drum is
being rotated at 150 rps, the recording current is applied to the
magnetic head Ha if the drum PG pulse goes high and to the magnetic
head Hc if the drum PG pulse goes low.
[0179] In the HD mode, all the four magnetic heads Ha, Hb, Hc and
Hd shown in FIG. 29 are used, and twenty tracks per field are
formed as shown in FIG. 30. FIG. 31 shows the timing of head
switching. While the rotary drum is being rotated at 150 rps, the
recording current is applied to the magnetic heads Ha and Hb if the
drum PG pulse goes high and to the magnetic heads Hc and Hd if the
drum PG pulse goes low.
[0180] FIG. 32 shows a flowchart of mode identification which is
executed during reproduction. First, the current reproduction mode
is confirmed (S1). In Step S2, the flow proceeds to any one of
Steps S3, S4 and S5 in accordance with the result of the
confirmation which indicates any one of the SD-Low mode, the
SD-High mode and the HD mode. Any value of "5", "10" and "20" is
set in a variable N (S2, S4 or S5).
[0181] The mode used during recording is identified on the basis of
the sub-code of a reproduced digital signal (S6 and S7), and the
subsequent reproduction mode is determined. In Step S7, the flow
proceeds to any one of Steps S8, S9 and S10 in accordance with the
determined mode which is any one of the SD-Low mode, the SD-High
mode and the HD mode. Any value of "5", "10" and "20" is set in a
variable M which determines the number of tracks per field (S8, S9
or S10).
[0182] The variables N and M are compared (S11). If N<M, the
running speed of the magnetic tape is increased (S12). If N=M, the
running speed of the magnetic tape is kept (S13). If N>M, the
running speed of the magnetic tape is increased (S14). In other
words, the running speed of the magnetic tape is controlled to
become equal to the tape speed specified by a mode selected during
recording.
[0183] After the completion of Step S12, S13 or S14, the flow
returns to Step S1, and the above-described processing is
repeated.
[0184] An embodiment of a video recording and reproducing apparatus
in which the down converter shown in FIG. 7 and the up converter
shown in FIG. 33 are used as broadcasting system converters will be
described below with reference to FIG. 34 as well.
[0185] FIG. 33 shows one example of an NTSC-HD system converter
which serves as the up converter. In the NTSC-HD system converter
shown in FIG. 33, an NTSC signal is decoded through a motion
adaptive type NTSC decoder 570, and the aspect ratio of the decoded
signal is converted from 4:3 to 16:9 in an aspect ratio conversion
part 571. Then, the number of scanning lines is converted from 525
to 1,125 in a number-of-scanning-lines conversion part 572, and the
field frequency is converted from 59.94 Hz to 60 Hz in a field
frequency conversion part 573. Thus, the NTSC signal is converted
into an HD signal to be outputted.
[0186] FIG. 34 is a block diagram showing a video recording and
reproducing apparatus according to another embodiment of the
present invention. An operator can select recording or
reproduction, HD mode or SD mode and the like on an operation panel
500. The following description refers to four kinds of operations
of the recording and reproducing system of the apparatus. The input
signal of this embodiment is an HD signal.
[0187] (1) Recording in SD Mode (Long-Time Recording Mode)
[0188] "RECORDING" and "SD" are selected on the operation panel
500, and a system controller 501 connects the movable contact of a
switch 506 to a contact {circle around (1)} or {circle around (2)}
thereof. An HD input signal is down-converted into an SD (for
example, NTSC) signal by a down converter 503. The system
controller 501 also controls a switch 502 to connect the movable
contact of the switch 502 to a contact {circle around (1)} thereof.
Thus, the SD signal is recorded on a tape 510 through a recording
system 509. During this time, an SD monitor 504 is used.
[0189] (2) Recording in HD Mode (High Definition Mode)
[0190] "RECORDING" and "HD" are selected on the operation panel
500, and the system controller 501 connects the movable contact of
the switch 502 to a contact {circle around (2)} thereof. The HD
input signal is directly recorded on the tape 510. During this
time, either one of an ED monitor 505 and the SD monitor 504 can be
selected.
[0191] If the HD monitor 505 is to be used, the movable contact of
the switch 506 is connected to the contact {circle around (1)} or
{circle around (2)} thereof so that the HD signal can be directly
outputted to the HD monitor 505.
[0192] If the SD monitor 504 is to be used, the movable contact of
the switch 506 is similarly connected to the contact {circle around
(1)} or {circle around (2)} thereof, and the HD signal is
down-converted into an SD signal by the down converter 503. By
connecting the movable contact of the switch 507 to any one
selected from the contacts {circle around (1)}, {circle around (2)}
and {circle around (4)} thereof, the SD signal can be outputted to
the SD monitor 504.
[0193] By adopting the above-described arrangement, it is possible
to provide a camera-integrated type VTR of reduced size.
[0194] (3) Reproduction in SD Mode
[0195] "REPRODUCTION" and "SD" are selected on the operation panel
500, and the system controller 501 connects the movable contact of
the switch 507 to a contact {circle around (3)} thereof. An SD
signal reproduced from the tape 510 by a reproducing system 511 is
displayed on the SD monitor 504 as a reproduced output image. If
the SD signal is to be displayed on the HD monitor 505, it is
converted into an HD signal by an up converter 508 and the movable
contact of the switch 506 is connected to a contact {circle around
(3)} thereof.
[0196] (4) Reproduction in HD Mode
[0197] "REPRODUCTION" and "HD" are selected on the operation panel
500, and the system controller 501 connects the movable contact of
the switch 506 to a contact {circle around (4)} thereof. A
reproduced HD signal is directly displayed on the HD monitor 505 as
a reproduced output image. If the HD signal is to be displayed on
the SD monitor 504, the movable contact of the switch 506 is
similarly connected to the contact {circle around (4)} and the HD
signal is converted into an SD signal by the down converter 503.
When the movable contact of the switch 507 is connected to a
contact {circle around (1)} thereof, the SD signal can be displayed
on the SD monitor 504. The following table shows the manner of
connection of the contacts {circle around (1)} to {circle around
(4)} of each of the switches 502, 506 and 507 during each of the SD
and HD modes. TABLE-US-00001 Recording Reproduction SD {circle
around (1)} {circle around (3)} HD {circle around (2)} {circle
around (4)}
[0198] Although in the above-described embodiment the up converter
508 is employed, a multi-scan monitor may also be used instead of
the HD monitor 505. In the case of the multi-scan monitor, the up
converter 508 can be omitted because if an SD (for example, NTSC)
signal is inputted, the SD signal is scanned by using 525 scanning
lines/frame. As the SD-Low mode, an SD signal having a horizontal
resolution of approximately 230 lines which is a standard image
quality in general domestic apparatus may also be applied to the
multi-scan monitor.
[0199] As can be readily understood from the above description, in
accordance with the above-described embodiment, since a compression
mode suitable for image compression processing to be executed in a
recording system is selected according to a photographic mode
selected in a image pickup system, a photographic image can be
efficiently compressed by the image compression processing, so that
good image quality and a high compression ratio can be
achieved.
[0200] Further, in accordance with the above-described embodiment,
in one camera-integrated type VTR, it is possible to achieve
selective utilization of a plurality of camera modes conforming to
a plurality of broadcasting systems. Also, the setting of a
compression mode, such as the selection of a compression ratio and
a compression system for an image, and the setting of the required
recording mode in a VTR can be automatically controlled by a system
controller in accordance with the selection of a camera mode.
Accordingly, it is possible to realize a camera-integrated type VTR
which can be utilized in a variety of applications by an easy
operation without the need to perform a complicated connection or
operation.
[0201] Also, in accordance with the above-described embodiment,
since a single down converter is used to perform recording of a
video signal input and reproduction of a recorded video signal, it
is possible to reduce the circuit scale of the apparatus, and it is
also possible to selectively record or reproduce an RD signal and
an SD signal. Also, it is possible to employ an SD monitor as an
output monitor for an HD signal input. Further, since the SD
monitor can be used as a monitor, it is possible to realize a
camera-integrated type VTR which is reduced in size compared to
conventional camera-integrated type VTRS.
[0202] In the above-described embodiment, the HD mode, the SD-Low
mode and the SD-High mode are prepared as the three recording
modes. However, the kinds of modes are not limited to these modes,
and it is also possible to use three modes such as HD, SD and ED
modes.
[0203] The manner of mode identification during reproduction and
the sequence of control to be executed for the mode identification
will be described below with reference to FIG. 35.
[0204] Step P1: The current reproduction running mode of a VTR is
confirmed.
[0205] Step P2: A variable N is set to N=10 or N=20 according to
which of the three modes is selected.
[0206] Step P3: A sub-code is detected from a reproduced digital
signal, and the mode used during recording is identified on the
basis of the sub-code of the reproduced digital signal, and the
required reproduction mode is determined.
[0207] Step P4: The required number of tracks per unit time M and a
data compression ratio CR are respectively set to M=10 or 20 and
CR=5 or 10 in accordance with any one of the three modes which is
indicated by reproduced ID data.
[0208] Step P5: The target value of capstan speed control is set in
accordance with the result of a comparison between the values of
the variables N and M.
[0209] The flow proceeds from Step P5 to any one of the succeeding
three steps.
[0210] If N>M, it is determined that the current speed is
greater than the speed used during recording, and the current speed
is decreased.
[0211] If N<M, it is determined that the current speed is
smaller than the speed used during recording, and the current speed
is increased.
[0212] If N=M, the current speed is kept.
[0213] Step P6: A data expansion ratio is set to 1/CR and decoding
is executed.
[0214] The flow returns to Step P1 for confirming the current mode,
and the above-described routine is repeated.
[0215] To obtain a better understanding of the operation of the
focusing control circuit 61 shown in FIG. 6, the relationship
between system conversion (conversion between television systems)
and TVAF (automatic focusing a video signal) will be described
below with reference to FIGS. 36 and 37.
[0216] The amount of information carried by an HDTV signal is
approximately five times that of information carried by an existing
broadcasting (SD) system. Further, the HDTV signal contains more
high-frequency spectrum components than the SD signal.
[0217] FIG. 36 shows the level variations of the amount of
high-frequency components contained in the respective signals
conforming to the two broadcasting systems with respect to the
movement of the focus of an image pickup optical system between its
closest-distance position and its infinity position. Both curves A
and B reach the respective peaks at an in-focus point.
[0218] The curve A indicates the variation curve of the HDTV
signal, while the curve B indicates the variation curve of the
existing TV signal. The relationship between the heights at the
in-focus point of the respective curves A and B is A.gtoreq.B.
[0219] The relationship between the widths of in-focus areas "a"
and "b" in which to restart an AF operation is a.ltoreq.b. A
sharper curve provides a smaller in-focus area for which AF
restarting computations must be executed more frequently. In
consequence, the curve A can achieve a better focusing
characteristic in terms of focusing accuracy.
[0220] In other words, if HDTV video information which contains a
larger amount of information is used, it is possible to achieve
TVAF of higher performance.
[0221] For this reason, in an image pickup system employing a down
converter, video information which is not yet processed by the down
converter is suitably used as information for the aforesaid
TVAF.
[0222] Incidentally, as shown in FIG. 37, signal frequency
components differ between the existing NTSC and PAL broadcasting
systems as well. Accordingly, if optimum ones of the signal
frequency components are selectively employed according to the kind
of subject or photographic conditions (the illuminance of
surroundings), it is possible to improve detection accuracy.
[0223] As shown in the coordinate plane of FIG. 37 which is defined
by three kinds of frequency axes, if it is assumed that the
horizontal frequencies of the NTSC and PAL video signals are the
same, the NTSC system provides a picture which is made up of 60
fields/second with respect to the temporal frequency axis and 525
scanning lines with respect to the vertical frequency axis.
Accordingly, the video signal components of the NTSC video signal
are present in the frequency area defined by 60/2 and 525/2.
[0224] The PAL system provides a picture which is made up of 50
fields/second with respect to the temporal frequency axis and 625
scanning lines with respect to the vertical frequency axis.
Accordingly, the video signal components of the PAL video signal
are present in the frequency area defined by 50/2 and 625/2.
[0225] By selectively utilizing the different characteristics in
accordance with the kind of subject whose image is to be picked up
and the kind of photographic mode, it is possible to further
improve the performance of TVAF.
[0226] The improvement of the performance of TVAF leads to not only
an improvement in the diameter of a circle of least confusion at a
final in-focus position but also an improvement in the stability of
the process of finding an in-focus position (for example, an
unstable behavior such as hunting or fluctuation can be
reduced).
[0227] As described above, a subject image is photoelectrically
converted by the CCD built in the HDTV camera 60 and an HD signal
having a high degree of definition and a large amount of
information is outputted.
[0228] An embodiment in which a concept called "scalability" is
applied to the hierarchical structure of image information of a VTR
to improve data handling will be described below with reference to
FIGS. 38 to 49.
[0229] A technique for performing coding or decoding and recording
or reproduction of HD information in a structure in which an NTSC
signal is included in the HD information will be described below
with illustrative reference to a two-layer structure consisting of
the HD information and the NTSC information.
[0230] First, encoding of an NTSC signal is performed and the
encoded sinal is transferred (or recorded).
[0231] Then, a non-transmitted or unrecorded information portion is
transferred (or recorded).
[0232] An operation which is performed by recording means having
the arrangement shown in FIG. 38 when an HD signal is inputted
thereto will be described below.
[0233] The input HD signal is down-converted into an SD signal by a
down converter 661, and the output of the down converter 661 is
inputted to an SD-signal encoder 662. The encoded SD signal is
divided into two channels by a recording channel divider 663, and
the two outputs of the recording channel divider 663 are supplied
to recording head amplifiers 671 and 673, respectively. Then,
information recording tracks are formed on a magnetic recording
medium 660 by magnetic recording heads 672 and 674. In the
meantime, the output of the SD-signal encoder 662 is supplied to an
SD-signal decoder 665 and, in an up converter 664, the output of
the SD-signal decoder 665 is converted into an HD signal which
contains an image distortion (error) occurring during
encoding/decoding. If this degradation signal (recording SD
information) is subtracted from the previous input signal, a
difference signal for forming an HD signal can be obtained. Such a
difference signal is formed by a subtractor 669, and the amount of
data contained in the difference signal is reduced in a data
compressor 666, and the output of the data compressor 666 is
inputted into a data formatter 667 for causing the SD signal to
conform to the recording standard of the HD signal. The output of
the data formatter 667 is divided into two channels by a recording
channel divider 668 similar to the aforesaid recording channel
divider 663. The thus-obtained HD additional information is
supplied to recording head amplifiers 675 and 677. Magnetic
recording heads 676 and 678 sequentially record and form a pair of
HD information recording tracks in an area adjacent to the pair of
SD information recording tracks formed by the outputs of the
divider 663 on the magnetic recording medium 660.
[0234] The manner of the above-described recording operation is
diagrammatically shown in FIG. 40.
[0235] The SD information and the HD additional information, which
are in the inclusive relationship shown by a symbolic block (left)
representative of the amount of image information, are respectively
recorded by two pairs of double azimuth (+/-) heads at the rate of
two tracks at one time, and a total of four tracks constitute a
basic unit.
[0236] The tape transporting speed used during the above-described
recording operation is selected to be two times the tape
transporting speed used during SD recording (N=2).
[0237] FIG. 39 is a schematic view showing the operation of an SD
recording mode for recording only the SD information on a recording
medium by one pair of double azimuth (+/-) heads at the rate of two
tracks at one time.
[0238] The tape transporting speed used during this recording
operation is selected to be a standard speed (N=1).
[0239] An example of the arrangement of reproducing means for
reproducing arbitrary information from a magnetic tape on which SD
information and HD additional information are recorded in the
above-described manner will be described below, and the reproducing
operation of the reproducing means will be described with reference
to FIG. 41.
[0240] Signals, which are respectively outputted from a pair of
magnetic heads 702 and 704 for tracing only a pair of SD
information recording tracks on a magnetic tape 709 recorded in an
HD recording mode, are respectively amplified by head amplifiers
701 and 703. The signals outputted from the head amplifiers 701 and
703 are integrated by a data combiner 693, and the output of the
data combiner 693 is decoded from its recording data format into an
SD signal, such as an NTSC signal, by an SD-signal decoder 692. The
SD signal is converted into an HD-signal format by an up converter
691. The processing of this SD-HD format conversion is the inverse
of the processing performed by the above-described down
converter.
[0241] Signals, which are respectively outputted from a pair of
magnetic heads 706 and 708 for tracing only a pair of HD additional
information recording tracks on the magnetic tape 709 recorded in
the HD recording mode, are respectively amplified by head
amplifiers 705 and 707. The signals outputted from the head
amplifiers 705 and 707 are integrated by a data combiner 697, and
the output of the data combiner 697 is decoded from its recording
data format into a compressed HD additional signal by an HD-signal
decoder 696. The compressed HD additional signal is converted into
an HD additional signal by a data expander 695.
[0242] The SD information and the HD additional information which
have been converted into a common HD signal format in the
above-described manner are added together by an adder 694, whereby
the original HD signal is reconstructed.
[0243] FIG. 42 schematically shows the manner of the
above-described reproduction from the magnetic tape recorded in the
HD recording mode.
[0244] Both the period during which a pair of magnetic heads for
tracing only a pair of HD additional information recording tracks
on a magnetic tape recorded in the HD recording mode trace the
magnetic tape and the period during which a pair of magnetic heads
for tracing a pair of SD information recording tracks on the
magnetic tape trace the magnetic tape are selected on the basis of
the angle over which the magnetic tape is wrapped around a head
drum. If each of the periods is selected to be 180 degrees, an HD
additional data reproduction period and an SD data reproduction
period appear alternately at intervals of one-half rotation of the
head drum.
[0245] During each of the data reproduction periods, the signals
recorded on two tracks are reproduced by either of the pairs of
double azimuth heads provided on the rotary drum. The signals
recorded on a total of four tracks are reproduced as a basic
unit.
[0246] Accordingly, the signals recorded on four tracks which
constitute the basic unit of the aforesaid information can be
reproduced during one rotation of the head drum. The inclusive and
combination relationships between the SD information and the HD
additional information which are reproduced in the above-described
manner are shown in the right-hand part of FIG. 42 by using
symbolic blocks each representative of the amount of image
information.
[0247] Compatible reproduction which is most important in the
present invention will be described below.
[0248] The following description refers to a case where an SD
recording apparatus having no recording function for the HD
recording mode is used to perform reproduction from a magnetic tape
recorded in the HD recording mode, as shown in FIG. 49.
[0249] FIG. 44 shows the manner in which a pair of magnetic heads
for tracing a pair of SD information recording tracks on a magnetic
tape recorded in the SD recording mode traces the magnetic tape to
reproduce an SD signal. Only one pair of double azimuth heads are
provided on a head drum, and SD information alone is recorded on
each track of the magnetic tape. In this case, each SD data
reproduction period occurs only once during one rotation of the
head drum. Since the tape transporting speed is the standard speed
(N=1), the SD information recorded on each recording track is
sequentially reproduced without skipping any of the recording
tracks. FIG. 44 schematically shows the manner of the
above-described reproducing operation.
[0250] If recording-mode identification information, such as ID, is
detected from a video area or a sub-code area by the detector 771
shown in FIG. 49 during the SD recording mode reproducing
operation, a compatible reproduction mode is selected. When a servo
circuit 773 receives an instruction from the detector 771, the
servo circuit 773 sets the current tape transporting speed to a
double speed equal to the tape transporting speed for the HD
reproduction mode. Incidentally, a motor 774 is provided for
driving a capstan, and a frequency generator (FG) 775 is provided
so that the servo circuit 773 can confirm the state of rotation of
the capstan.
[0251] The pair of double azimuth heads for SD signals, which are
provided on the head drum, trace only pairs of SD information
recording tracks on a magnetic tape recorded in the HD recording
mode. However, since no magnetic heads for HD signals are provided,
the magnetic tape is transported without tracing a pair of HD
additional information tracks. Accordingly, an HD addition data
track idle running period and an SD data reproduction period
alternately appear at intervals of one-half rotation of the head
drum. FIG. 43 schematically shows the manner of the above-described
reproducing operation.
[0252] Reproduction from only two tracks for SD signals out of four
tracks which constitute one basic unit is performed by the pair of
double azimuth (+/-) heads provided on the rotary drum, at
intervals of one rotation period.
[0253] The signal reproduced in the above-described manner is
converted into an SD signal, such as an NTSC or PAL signal, by the
SD-signal decoder 772 shown in FIG. 49, and the SD signal is
outputted from the SD-signal decoder 772. The manner of the
above-described reproduction from the recorded tracks is shown in
FIG. 45 in the form of a recording track pattern.
[0254] The recording tracks shown in FIG. 45 constitute groups each
consisting of four tracks indicated by characters "a" to "d"
affixed to the respective numbers.
[0255] The characters "a" and "b" indicate tracks for SD signals
(represented by meshes), and the characters "c" and "d" indicate
additional tracks for HD signals.
[0256] In the compatible reproduction mode, reproduction from only
the tracks "a" and "b" is performed, and no reproduction from the
track "c" nor "d" is performed.
[0257] FIG. 46 is a graphic representation showing a head relative
speed Vhead determined by a tape transporting speed Vtape and a
head drum rotational speed Vdrum, and the horizontal and vertical
axes represent the tape transporting speed Vtape and the head drum
rotational speed Vdrum, respectively.
[0258] Since the head relative speed Vhead reaches 9,000 rotations
during the SD mode, it is not practical to increase the rotational
speed to a further extent for the purpose of coping with the HD
mode. If the rotational speed is selected to be not less than 9,000
rotations, two kinds of trace angles are formed in the case of the
respective standard and double speeds, as shown in FIG. 46.
[0259] A line V1 indicates the case of reproduction of an SD mode
recording, and a line V2 indicates the case of reproduction of an
HD mode recording. In the case of the compatible reproduction mode
according to the present embodiment, the tape transporting speed
Vtape and the drum rotation speed Vhead are completely the same as
those used in the HD reproduction mode, the head trace V2 is
selected so that an SD track portion can be traced without any
problem. Each of FIGS. 47 and 48 is a table showing whether each of
the SD and HD reproduction modes can be used for magnetic tapes
recorded in the respective SD and HD recording modes, and FIG. 47
shows the case of an SD signal reproducing apparatus, while FIG. 48
shows the case of an HD signal reproducing apparatus.
[0260] As can be seen from FIGS. 47 and 48, not only the HD signal
reproducing apparatus but also the SD signal reproducing apparatus
can effect reproduction from any of the magnetic tapes recorded in
the SD recording mode or the HD recording mode.
[0261] It is to be noted that since reproduction from a magnetic
tape recorded in the SD recording mode can be performed in the
HD-signal format, "recording mode SD/reproduction mode HD" of FIG.
48 can also be regarded as "possible" although the image quality,
such as resolution, is equivalent to SD quality.
[0262] In the present embodiment, although the concept of a
hierarchical coding system has been described with illustrative
reference to pyramidal coding, the kind of coding system is not
limited to the pyramidal coding. For example, another hierarchical
coding technique, such as sub-band coding, can of course be used
without departing from the scope and spirit of the present
invention.
[0263] Incidentally, the head relative speed Vhead is not limited
to 9,000 rotations, and, for example, 4,500 rotations may be
selected. It is also possible to adopt an arrangement which
switches the head relative speed Vhead as well as the
characteristics of its control system on the basis of a decision as
to whether the HD mode or the SD mode is selected.
[0264] According to the embodiment utilizing the above-described
scalability, it is possible to achieve a remarkable improvement in
the characteristic of compatible reproduction from a recorded
medium, which cannot be attained by conventional image recording
systems because of their different coding systems.
[0265] Also, it is possible to effect reproduction from a recording
medium recorded in any recording mode, by means of not only
higher-order equipment but also lower-order equipment.
[0266] Furthermore, since a lower-order system needs only to have a
servo mechanism for effecting switching between media driving
speeds, users can easily introduce lower-order systems without
making large prior investments.
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